Deposition apparatuses

ABSTRACT

The invention includes deposition apparatuses having reflectors with rugged reflective surfaces configured to disperse light reflected therefrom, and/or having dispersers between lamps and a substrate. The invention also includes optical methods for utilization within a deposition apparatus for assessing the alignment of a substrate within the apparatus and/or for assessing the thickness of a layer of material deposited within the apparatus.

RELATED PATENT DATA

This patent resulted from a divisional of U.S. patent application Ser.No. 10/822,060, filed Apr. 8, 2004, which is hereby incorporated byreference.

TECHNICAL FIELD

The invention pertains to deposition apparatuses, to methods ofassessing alignment of substrates within deposition apparatuses, and tomethods of assessing thicknesses of deposited layers within depositionapparatuses.

BACKGROUND OF THE INVENTION

Integrated circuitry fabrication includes deposition of materials andlayers over semiconductor wafer substrates. One or more substrates arereceived within a deposition chamber within which deposition typicallyoccurs. One or more precursors or substances are caused to flow to asubstrate, typically as a vapor, to effect deposition of a layer overthe substrate. A single substrate is typically positioned or supportedfor deposition by a susceptor. In the context of this document, a“susceptor” is any device which holds or supports at least one waferwithin a chamber or environment for deposition. Deposition may occur bychemical vapor deposition, atomic layer deposition and/or by othermeans.

FIGS. 1 and 2 diagrammatically depict a prior art susceptor 12, andvarious issues associated therewith. Susceptor 12 receives asemiconductor wafer substrate 14 (shown in dashed-line view in FIG. 2)for deposition. Substrate 14 is received within a pocket or recess 16 ofthe susceptor to elevationally and laterally retain substrate 14 in thedesired position.

A particular exemplary system is a lamp heated, thermal depositionsystem having front and back side radiant heating of the substrate andsusceptor for attaining and maintaining desired temperature duringdeposition. FIG. 2 depicts a thermal deposition system having at leasttwo radiant heating sources for each side of susceptor 12. Depicted arefront side and back side peripheral radiation emitting sources 18 and20, respectively, and front side and back side radially inner radiationemitting sources 22 and 24, respectively. Incident radiation fromsources 18, 20, 22 and 24 overlaps on the susceptor and substrate,creating overlap areas 25. Such can cause an annular region of thesubstrate corresponding in position to overlap areas 25 to be hotterthan other areas of the substrate not so overlapped. Further, the centerand periphery of the substrate can be cooler than even the substratearea which is not overlapped due to less than complete or even exposureto the incident radiation.

The susceptor is typically caused to rotate during deposition, withdeposition precursor gas flows occurring across the wafer substrate. AnH₂ gas curtain (not shown) will typically be provided within the chamberproximate a slit valve (not shown) through which the substrate is movedinto and out of the chamber. A preheat ring (not shown) is typicallyreceived about the susceptor, and provides another heat source whichheats the gas flowing within the deposition chamber to the wafer. Inspite of the preheat ring, the regions of the substrate proximate wheregas flows to the substrate can be cooler than other regions of thesubstrate.

Robotic arms (not shown) are typically used to position substrate 14within recess 16. Such positioning of substrate 14 does not alwaysresult in the substrate being positioned entirely within susceptorrecess 16. Further, gas flow might dislodge the wafer such that it isreceived both within and without recess 16. Such can further result intemperature variation across the substrate and, regardless, result inless controlled or uniform deposition over substrate 14.

The sources 18, 20, 22 and 24 can be lamps provided directly oversurfaces which are to be exposed to radiation, or can be light directedfrom lamps which are remote from the surface to which radiation is to bedirected. Such aspects of the prior art are shown in FIGS. 3 and 4.Specifically, FIG. 3 diagrammatically shows sources 18 and 22 as lampsprovided over a surface of the substrate 14 retained within susceptor12. The lamps 18 and 22 have surfaces closest to substrate 14 from whichemitted light is directed toward substrate 14, and have opposingsurfaces from which emitted light is directed away from substrate 14.The surfaces near substrate 14 can be considered forward surfaces, andthe opposing surfaces can be considered rearward surfaces. A pluralityof reflectors 30 can be provided to reflect light emitted from therearward surfaces of lamps 18 and 22 toward substrate 14. Emitted lightis diagrammatically illustrated in FIG. 3 by arrows 32 (only some ofwhich are labeled), and such arrows show light emitted directly towardsubstrate 14, and also show light reflecting from reflectors 30 towardsubstrate 14. Reflectors 30 can have the shown curved shapes, or can besubstantially flat.

Referring to FIG. 4, a pair of lamps 18 is shown remote from a surfaceof substrate 14 (the lamps 22 are not shown in FIG. 4 in order tosimplify the drawing, and the lamps 20 and 24 are not shown in either ofFIGS. 3 and 4, again to simplify the drawings). A pair of mirrors 34 isshown over substrate 14. Light 32 is directed from lamps 18 towardmirrors 34, and then reflected from the mirrors 34 toward substrate 14.

Various problems can exist with the prior art apparatuses described withreference to FIGS. 1-4. For instance, there can be problems with unevenheating across a substrate, as described above, and there can also beproblems with the substrate wobbling or otherwise being improperlyaligned within the susceptor. Additionally, there can be problems inobtaining uniform deposition of materials across the substrate, inascertaining if the deposition across the substrate is uniform, and inascertaining the approximate thickness of the deposition across thesubstrate. It is desired to develop improved susceptor apparatus designsand methodologies for utilizing susceptor apparatuses which address oneor more of such problems. However, although the invention was motivatedfrom this perspective and in conjunction with the above-describedreactor and susceptor designs, the invention is not so limited. Rather,the invention is only limited by the accompanying claims as literallyworded, without interpretive or other limiting reference to thespecification and drawings, and in accordance with the doctrine ofequivalents.

SUMMARY OF THE INVENTION

In one aspect, the invention includes a deposition apparatus. Theapparatus comprises a substrate susceptor for receiving a substrate andone or more lamps for providing radiant energy to the substrate.Further, the apparatus includes a reflector associated with at least oneof the lamps and configured for directing radiant energy from the lamptoward the substrate. The reflector has a rugged reflective surfaceconfigured to disperse the light reflected therefrom.

In one aspect, the invention encompasses a deposition apparatus whichincludes a disperser between a lamp and a substrate. The apparatus isconfigured such that at least some light waves emitted from the lamp arepassed through the disperser and then utilized for providing radiantenergy to the substrate.

In one aspect, the invention encompasses a method of assessing alignmentof a substrate within a deposition apparatus. A deposition apparatus isprovided to have a substrate susceptor for receiving a substrate, tohave one or more laser emitters, and to have one or more photodetectors.A substrate is provided to be received by the susceptor. Light isemitted from at least one of the laser emitters toward the substrate andreflected from the substrate to at least one of the photodetectors. Theemitted light is detected with the photodetector, and informationpertaining to the detected light is utilized to assess alignment of thesubstrate.

In one aspect, the invention encompasses a method for assessing thethickness of a deposited layer utilizing optical methods for determininga thickness of a material over a surface of a susceptor. The opticalmethods can include, for example, ellipsometry.

In one aspect, the invention includes a method of assessing thethickness of a deposited layer within a deposition apparatus. Theapparatus includes one or more laser emitters and one or morephotodetectors. The apparatus also includes a susceptor. A substrate isprovided to be received by the susceptor, and the layer is depositedonto the substrate. Light is emitted from at least one of the laseremitters toward the substrate and reflected from the substrate to atleast one of the photodetectors. The reflected light is detected by thephotodetector and information pertaining to the detected light isutilized to assess the thickness of the deposited layer.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 is a top view of a prior art susceptor.

FIG. 2 is a cross-section of the FIG. 1 susceptor taken through the line2-2 of FIG. 1.

FIG. 3 is a diagrammatic, cross-sectional view of a portion of a priorart deposition apparatus illustrating an exemplary lamp arrangement.

FIG. 4 is a diagrammatic, cross-sectional view of a portion of a priorart deposition apparatus having an alternative lamp arrangement relativeto the FIG. 3 apparatus.

FIG. 5 is a diagrammatic, cross-sectional view of a deposition apparatusencompassing an aspect of the present invention.

FIG. 6 is a diagrammatic top view of a reflector suitable forutilization in an exemplary aspect of the present invention.

FIG. 7 is a diagrammatic, cross-sectional view of a portion of adeposition apparatus comprising an aspect of the present invention.

FIG. 8 is a diagrammatic, cross-sectional view of a portion of adeposition apparatus illustrating overlap of light from adjacent lampson a substrate.

FIG. 9 is a fragmentary top view of a portion of the substrate of FIG. 8further illustrating the overlap of light from adjacent lamps.

FIG. 10 is a diagrammatic, cross-sectional view of a portion of adeposition apparatus comprising an aspect of the present invention.

FIG. 11 is a top view of a portion of a deposition apparatus comprisingan aspect of the present invention.

FIG. 12 is a diagrammatic, cross-sectional view of a depositionapparatus comprising an aspect of the present invention.

FIG. 13 is a diagrammatic, cross-sectional view of a susceptor at apreliminary processing stage of an aspect of the present invention.

FIG. 14 is a view of the FIG. 13 susceptor having a substrate providedtherein, and shown at a processing stage subsequent to that of FIG. 13.

FIG. 15 is a view of the FIG. 13 susceptor having the substrate providedtherein, and is shown at a processing stage subsequent to that of FIG.14.

FIG. 16 is a view of the FIG. 13 susceptor shown at a processing stagesubsequent to that of FIG. 15.

FIG. 17 is a view of the FIG. 13 susceptor shown at a processing stagesubsequent to that of FIG. 16.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

FIG. 2 of the “Background” section of this disclosure shows anarrangement utilized for heating a semiconductor wafer during adeposition process. The construction of FIG. 2 is typical ofconstructions utilized for selective epitaxial growth of silicon orsilicon/germanium, and can also be utilized for other depositionprocesses, including other processes in which silicon or othersemiconductor materials are grown. The substrate 14 of FIG. 2 is dividedinto regions which are heated from upper and lower banks of lamps. Theregions can be divided into inner and outer zones, as described in the“Background” section of this disclosure.

The upper bank of lamps of the FIG. 2 apparatus will heat the waferprimarily through radiant heating, and the lamps will typically bedirectly over the wafer. The lower zone of the wafer of FIG. 2 will bealso heated with radiant heating, but typically not directly from thelamps since the wafer sits on an opaque wafer platform (the susceptor12) which has only edge contact with the wafer.

A problem with the configuration of FIG. 2 is that overlap regions(regions 25 of FIG. 2) will typically endure more intense heating thanother regions, which can lead to a donut/annulus of higher temperaturematerial associated with portions of the wafer exposed to the overlapregions. One aspect of the present invention is a recognition thatdiffusion of the radiant energy from the lamps can be advantageous.Specifically, diffusion of the radiant energy can spread the hot spotsassociated with overlap regions over wider areas, which can ultimatelylead to better temperature uniformity than is achieved with prior artapparatuses. The radiant energy is light, with term “light” being usedherein to refer to any suitable electromagnetic radiation. Accordingly,the term “light” can include, but is not limited to, light in thevisible wavelengths.

FIG. 5 illustrates one method which can be utilized for increasingdiffusion of light from lamps 18 and 22. Specifically, FIG. 5 shows aportion of an apparatus 50 comprising the susceptor 12 and substrate 14described previously in the “Background” section of this disclosure, andfurther comprising the lamps 18 and 22 (the apparatus 50 could furthercomprise the light sources 20 and 24, but such light sources are notshown in the diagram of FIG. 5 in order to simplify the drawing). Eachof the lamps 18 and 22 has a reflector 52 associated therewith. Thereflectors have rugged surfaces 53 which disperse light more than theprior art smooth surfaces associated with reflectors 30 (FIG. 3) of theprior art. The reflected light is shown by arrows 32 (only some of whichare labeled) in FIG. 5. Although four lamps are shown, it is to beunderstood that more than four or less than four lamps can be utilized.Also, although each of the lamps is shown associated with a reflectorhaving the rugged surface 53, it is to be understood that the inventionencompasses aspects in which less than all of the lamps are associatedwith the shown reflectors. Although FIG. 5 shows the reflectorsassociated only with a top bank of lamps, it is to be understood thatthe reflectors could additionally, or alternatively, be associated withone or more lamps of the bottom bank (the lamps 20 and 24 of FIG. 2).

The rugged reflective surface 53 can comprise any suitable structure. Insome aspects, the rugged reflective surface will comprise a repeatingpattern, such as, for example, a repeating honeycomb pattern or arepeating pattern of dimples. In other aspects, the reflective surfacecan comprise a relatively random structure, such as, for example, acrinkled foil structure. FIG. 6 shows a top view of a reflector. Theillustrated top view is toward the reflector 53, which corresponds to abottom view in the structure of FIG. 5, but which would typically bereferred to as a top view in the art. The reflector 52 of FIG. 6comprises a rugged surface 53 corresponding to a repeating honeycombpattern. Such repeating pattern is but one of many suitable repeatingpatterns, and can be an example of a repeating dimpled pattern. Therepeating honeycomb pattern would typical be across a substantialentirety (or a total entirety) of a rugged portion of the surface of theFIG. 6 reflector utilized for reflecting radiation toward the substrate,and is shown broken up in FIG. 6 to convey a sense that the FIG. 6reflector is concavely-curved.

FIG. 7 illustrates another aspect of the invention which can be utilizedfor diffusing radiation. Specifically, FIG. 7 illustrates an apparatus60 comprising the susceptor 12 and substrate 14 described previously,and comprising a top bank of lamps in which the lamps 18 are remote fromwafer 14 rather than directly over the wafer. The lamps 22 are not shownin the diagram of FIG. 7 in order to simplify the drawing, but it is tobe understood that lamps 22 can also be remote from the surface 14similarly to the lamps 18, or can be directly over the surface 14 eventhough the lamps 18 are remote. Radiation 32 (i.e. light waves) isdirected from lamps 18 toward a mirror 34 of the type describedpreviously relative to FIG. 4, and thereafter is directed toward asurface of substrate 14. However, in contrast to the prior art structureof FIG. 4, radiation 32 passes through a first disperser 62 prior tomirror 34, and then passes through a second disperser 64 after mirror34. Accordingly, the radiation 32 is split into multiple units, or inother words is dispersed prior to reaching the surface of substrate 14.

The first and second dispersers 62 and 64 can comprise any suitableunits which can disperse light waves, including, for example,diffraction gratings.

Although two dispersers are utilized in the shown aspect of theinvention, it is to be understood that more than two dispersers can beutilized, or only one disperser can be utilized. Also, although thedispersers are shown on both sides of mirror 34, it is to be understoodthat the invention encompasses other aspects in which dispersers areonly provided upstream of mirror 34, or only provided downstream ofmirror 34, rather than being both upstream and downstream of the mirroralong the light path. Additionally, the invention encompasses aspects inwhich the dispersers are utilized without also utilizing a mirror.

The dispersers of FIG. 7 can be combined with the reflectors of FIG. 5in some aspects of the invention. For instance, the reflectors of FIG. 5can be utilized with the upper bank of lamps (lamps 18 and 22 of FIG.2), and the dispersers of FIG. 7 can be utilized with the lower bank oflamps (the lamps 20 and 24 of FIG. 2). Alternatively, or additionally,both the reflectors and dispersers can be utilized with a single lamp sothat light is reflected off of a rugged reflector surface and thendirected through a disperser as the light is directed toward substrate14.

The lamps 18 and 22 of FIGS. 5 and 7 can be either within a reactionchamber associated with a deposition apparatus or external to thereaction chamber. If the lamps are external of the reaction chamberrelative to the aspect of FIG. 7, the dispersers can be either withinthe reaction chamber, or external to the reaction chamber, or some ofthe dispersers can be within the reaction chamber while others areexternal to the reaction chamber.

FIG. 8 shows an apparatus of the present invention in a view similar tothat utilized in FIG. 2 for showing a prior art apparatus, but onlyshows the top bank of radiant energy sources (18 and 22) even thoughboth banks would typically be utilized in the aspect of FIG. 8. Theradiant energy from the sources 18 is labeled as 19 in FIG. 8, and theradiant energy from sources 22 is labeled as 23 in FIG. 8. The radiantenergy from sources 18 and 22 is shown to be much more disperse in theaspect of FIG. 8 than in the prior art aspect. Accordingly, there isoverlap over substantially entirely all of the substrate 14 which cansignificantly reduce, and even eliminate, the problematic hot spotsexisting within prior art apparatuses. An amount of overlap between thepair of adjacent inner light sources 22 is cross-hatched in FIG. 8, andshown as a length “X” across the top of wafer 14. The length “X” is atleast about 50% of the total length of light from the source 22impacting substrate 14, with such total length being shown as the length“Y” in FIG. 8. In particular aspects of the invention, the amount ofoverlap can be at least 50%, and in some aspects greater than 70%, andin yet other aspects greater than 90% of the total length impacting asurface of substrate 14.

It is noted that the cross-sectional view of FIG. 8 shows the light fromsource 22 impacting substrate 14 as a length, but that in athree-dimensional view the light from source 22 would actually be a coneand would impact surface 14 in a circular or elliptical shape. FIG. 9shows a top view of a fragment of the FIG. 8 structure, and showselliptical light beams 23 overlapping. The overlap of the light beamscan be quantitated as the amount of surface area of substrate 14 whichis impacted by one light beam and also impacted by the adjacent lightbeam, relative to the amount of area impacted by the one light beam andnot by the adjacent light beam. In some aspects of the invention, atleast 50% of the radiant energy impacting the substrate from one lamp isoverlapped by radiant energy impacting the substrate from an adjacentlamp. The amount of overlap in particular aspects can be greater than60%, greater than 70%, greater than 80%, or even greater than 90%.

Another aspect of the invention pertains to methodology for assessingalignment of a substrate within a deposition apparatus. Such aspect isdescribed with reference to FIGS. 10 and 11. Referring initially to FIG.10, an apparatus 70 comprises the susceptor 12 and substrate 14described previously. The apparatus further comprises a light source (oremitter) 72 and a light detector 74. The source 72 is mounted through asupport 76 to apparatus 70 at a location proximate susceptor 12, and thedetector 74 is mounted through a support 78 to apparatus 70 at alocation which is also proximate susceptor 12. The susceptor can bewithin a reaction chamber, and one or both of the source 72 and detector74 can be within the chamber, or alternatively one or both of the source72 and detector 74 can be external to the chamber.

Source 72 can be any suitable source of light, and in particular aspectswill be a laser emitter. Detector 74 can be any suitable detector, andin particular aspects will be a photodetector configured to detectreflected laser light. Any suitable number of emitters and detectors canbe utilized, with the emitters and detectors typically provided inpaired configurations so that each emitter is in one-to-onecorrespondence with a detector.

In operation, emitter 72 emits light toward a surface of substrate 14,with such light being diagrammatically illustrated by dashed line 80.The light reflects off from the substrate toward detector 74. Thedetector then detects the light, and information about the detectedlight is utilized to assess alignment of the substrate. In some aspectsof the invention, the detector can be in data communication with asignal processor (not shown). Information about the detected light issent from the detector to the signal processor as a data signal (whichcan be, for example, an electrical signal), and the data processorprocesses the information to assess the alignment of the substrate. Theinformation can include the intensity of the light and/or the locationof the light. If the substrate is wobbling or otherwise misalignedwithin susceptor 12, the light detected by the detector will bedifferent than if the substrate is stable and properly aligned withinsusceptor 12. The detection of misalignment can be enhanced ifreflection points from the wafer surface are near a periphery of thewafer than near the center, as offsets from misalignment tend to be moreexaggerated at the wafer periphery than at the wafer center. Ifmisalignment is detected, the signal processor can be configured to makeadjustments which automatically correct for the misalignment, to triggeran alarm alerting an operator to the misalignment, and/or to shutdownthe deposition apparatus. Thus, the misalignment assessment of thepresent invention can be utilized for process monitoring and/or forautomatic process control.

The alignment assessment of FIG. 10 can be particularly useful forapplication to epitaxial growth of semiconductor materials, such as, forexample, epitaxial growth of silicon, including procedures whichselectively epitaxially deposit silicon on particular surfaces relativeto others. It is found that misalignment or improper leveling of thesubstrate by 0.005 inches can result in non-uniform films. Prior artmethodologies utilized a level to check alignment of wafers, but such isdifficult to accomplish in small chambers, and even when the chambersare large enough, it is difficult to obtain the desired accuracy with alevel. Further, it is difficult to employ a level for checking alignmentof a spinning substrate. Methodology of the present invention can beutilized to assess alignment of a wafer continuously from an initialperiod before spinning starts, through the spinning of the wafer, anduntil a period after the spinning of the substrate has stopped.Alignment in accordance with particular aspects of the present inventioncan advantageously be conducted with greater precision, betterreproducibility/accuracy and better wafer-to-wafer uniformity than priorart methods.

In some aspects, two to four pairs of laser emitters and detectors aremounted around a susceptor. Susceptor adjustments are made while thesusceptor is stationary (not spinning) until all of the laser beamsreflect onto corresponding detectors to achieve maximum signals by thedetectors (i.e., the detectors and laser emitters are configured so thatmaximum signals are received by the detectors when the wafer is properlyaligned). The susceptor/wafer combination is then spun, and thealignment is fine-tuned by making further adjustments to maximize thesignals detected by the detectors. In particular aspects, the signalsreceived by the detectors can be considered to be approximatelymaximized during an alignment process, rather than entirely maximized,with the term “approximately maximized” indicating that the signals arebrought to within desired tolerances of a maximum signal.

FIG. 11 shows a top view of a construction 90 that can be utilized in anexemplary aspect of the invention. Construction 90 comprises laseremitters 92, 94 and 96, which are paired with photodetectors 98, 100 and102, respectively. The laser emitters and detectors are arranged arounda susceptor 12 having a substrate 14 retained thereby. The shownconfiguration has three pairs of laser emitters/detectors. It is to beunderstood, however, that the invention encompasses aspects in whichless than three pairs of laser emitters/detectors are utilized or morethan three pairs of laser emitters/detectors are utilized.

The above-described process of utilizing light for detection ofalignment can be considered an optical method of alignment assessment(with the term “optical method” referring to a method utilizing light,which may or may not be visible-wavelength light). In some aspects ofthe invention, optical methods can be utilized for assessing thethickness of a deposited layer in addition to, or alternatively to,assessing alignment of a wafer within a deposition apparatus. FIG. 12shows an apparatus 110 comprising a light source 112 and a lightdetector 114, and configured for assessing the thickness of a depositedlayer. Source 112 can comprise, for example, a laser emitter, anddetector 114 can comprise, for example, a photodetector. Emitter 112 isattached to apparatus 110 with a support structure 116, and detector 114is attached to apparatus 110 with a support structure 118. Emitter 112and detector 114 can be the same as the emitter 72 and detector 74described above with reference to the aspect of FIG. 10, or can bedifferent.

The emitter 112 and detector 114 are shown proximate a susceptor 12 andsubstrate 14. In practice, susceptor 12 and substrate 14 would be withina reaction chamber. One or both of emitter 112 and detector 114 can bewithin the reaction chamber, or alternatively one or both of emitter 112and detector 114 can be external of the reaction chamber. If an emitterand/or detector is external of the reaction chamber, the light passingbetween the emitter and detector can be passed through one or morewindows formed in sidewalls of the reaction chamber.

Light emitted from emitter 112 is labeled as shown in dashed line in thediagram of FIG. 12, and labeled 120. Initially, light is emitted fromemitter 112 toward an upper surface of substrate 14 and then detected bydetector 114. The detected light is utilized to establish a base signalwhich can be correlated with a starting elevational level of the surfaceof substrate 14. Specifically, the light reflecting from the surface 14follows a path 121 and impacts a first location 122 of a face ofdetector 114. The location 122 of the impact point of path 121 can beconsidered a termination point of an emitted signal, in some aspects ofthe invention.

Detector 114 can be in data communication with a signal processor 117,as shown. Information about detected light is sent from the detector tothe signal processor as a data signal 115 (which can be, for example, anelectrical signal), and the data processor processes the information toassess the thickness of a deposited material. Accordingly, the signalprocessor can process a data signal from the detector to recognize thatlight impact location 122 of the detector face corresponds to zerogrowth of deposited material. Such can be referred to as calibration ofthe signal processor.

After the signal processor is calibrated, a material 15 is depositedover the surface of substrate 14 (material 15 is shown in dash-line viewin FIG. 12). Light from emitter 112 is directed toward substrate 14, butnow impacts a surface of deposited material 15, and thus the reflectedlight takes a new path 123. The light along path 123 impacts a face ofdetector 114 at a location 124 displaced from location 122. The shift ofthe termination point of emitted signal 120 from location 122 tolocation 124 can be ascertained by signal processor 117 and correlatedto a thickness of the layer 15 being deposited. In some aspects, thesignal processor can be configured to detect when a desired thickness oflayer 15 is deposited and to initiate an automated response. Thus, thefilm thickness measurement of the present invention can be utilized forprocess monitoring and/or for automatic process control. In particularaspects of the invention, the thickness monitoring can be utilized as anautomatic process control trigger for step-end control.

Although the process of FIG. 12 shows only one emitter and one detector,it is to be understood that a process of the present invention canutilize more than one emitter and/or more than one detector.

Utilization of laser emitters or other light emitters to assessalignment and/or thickness of deposited layers can be advantageous inthat the emitters can be utilized in situ during a deposition process tomonitor the process. Further, the utilization of the emitters can beconducted without adversely impacting process time, temperature or gasflow in a reaction chamber. Measurement during film growth can enablefilm growth and uniformity to be correlated with properties of a waferafter the processing (and, in some aspects, after cooling) and/or withperformance of devices formed over the wafer. The light utilized in thevarious aspects of the invention for assessing growth and/or alignment(e.g., the light 80 of FIG. 10 and the light 120 of FIG. 12) can be anysuitable wavelength, and typically will be a wavelength which does notalter materials associated with a surface of substrate 14 or depositedover the surface of substrate 14.

FIGS. 13-17 illustrate further methodology by which optical methods canbe utilized for assessing the thickness of a deposited layer within adeposition apparatus. In such aspects, growth of material over asusceptor surface is measured and utilized to estimate growth of thesame material over a surface of a semiconductor substrate. To aid ininterpretation of the claims that follow, the terms “semiconductivesubstrate” and “semiconductor substrate” are defined to mean anyconstruction comprising semiconductive material, including, but notlimited to, bulk semiconductive materials such as a semiconductive wafer(either alone or in assemblies comprising other materials thereon), andsemiconductive material layers (either alone or in assemblies comprisingother materials). The term “substrate” refers to any supportingstructure, including, but not limited to, the semiconductive substratesdescribed above.

Referring initially to FIG. 13, a susceptor 12 is illustrated at apreliminary processing stage. Susceptor 12 comprises the recess 16described previously, a trough 130 beneath the recess, and uppermostouter surfaces 132 outwardly adjacent of the recess.

A first material 134 is deposited over the outermost surfaces 132. Firstmaterial 134 forms a layer over which subsequent deposition can occur.Specifically, in processing described below a material will be depositedover a semiconductor substrate and over the surfaces 132 of susceptor12. It can be desired that the deposition of the material occur atapproximately the same rate over surfaces 132 as over a surface of thesubstrate. Material 134 can be considered a treatment of surfaces 132which enhances deposition over the surfaces 132. For instance, susceptor12 can comprise silicon carbide at surfaces 132 and such silicon carbidecan be relatively porous such that deposition over the silicon carbidewill occur at a different rate than deposition over a semiconductorwafer substrate. Material 134 can be provided over the silicon carbidesurface 132 to provide a new upper surface (surface 136) upon whichdeposition will occur at approximately the same rate as the depositionover a semiconductor material wafer retained by susceptor 12.

Another application for utilizing layer 134 occurs in aspects in whichthe deposition occurring over a semiconductor material wafer isselective for a material other than the composition of upper surface132. Accordingly, material 134 is provided to provide a new uppersurface 136 for which the deposition is not selective, and accordinglyupon which the deposition will occur. In exemplary applications, asemiconductor material is to be epitaxially grown, and surface 132comprises silicon dioxide. The epitaxial growth may be selective formaterial other than silicon dioxide, and accordingly it is advantageousto form the material 134 over surface 132, with material 134 beingsilicon, germanium or silicon/germanium so that epitaxial growth ofsemiconductor material readily occurs over material 134.

Although material 134 is shown in the aspect of FIG. 13, it is to beunderstood that material 134 is optional and can be omitted in otheraspects of the invention. For instance, if surface 132 has a suitablecomposition so that deposition of a material over surface 132 will occurduring deposition of the material over a semiconductor wafer substrate,and will occur at a desired rate, then it may be suitable to omitmaterial 134.

Material 134 can comprise any suitable material or combination ofmaterials. For instance, material 134 can, in particular aspects,comprise, consist essentially of, or consist of doped or undopedsilicon, germanium or silicon/germanium.

Material 134 is shown formed only over surface 132, rather than oversurfaces of recess 16 or trough 130. This can be accomplished byappropriate masking of surfaces of recess 16 and trough 130 duringformation of material 134. In some aspects of the invention (not shown)material 134 can be formed over surface 132, and additionally can beformed over surfaces of one or both of recess 16 and trough 130.

Referring to FIG. 14, the semiconductor wafer substrate 14 is providedwithin recess 16. Substrate 14 has an upper surface 140. Substrate 14covers a first portion of the susceptor (for example, covers the troughportion 130 of the susceptor) and leaves a second portion not covered(for example, the surfaces 132 are not covered by the substrate 14).

Referring to FIG. 15, a material 142 is deposited over surface 136 ofmaterial 134, and also over surface 140 of semiconductor wafer substrate14. Materials 134 and 142 can be referred to as first and secondmaterials, respectively, and can be compositionally the same as oneanother or can be compositionally different from one another. Material142 can comprise any suitable material, including, for example,materials comprising, consisting essentially of, or consisting of one orboth of silicon and germanium. In some aspects, material 142 will beepitaxially grown silicon which is selectively grown over semiconductivematerial surfaces, such as, for example, surfaces comprising silicon orgermanium. In such aspects, it can be desired that material 134comprise, consist essentially of, or consist of silicon and/orgermanium.

The thickness of material 142 over surface 132 (specifically, thethickness of material 142 over layer 134 in the aspect of FIG. 15) ismeasured by an optical method. Light is represented by the dashed line150, and such light is associated with the optical method utilized tomeasure the thickness of material 142 over surface 132.

The optical method utilized can be a method of the type described withreference to FIG. 12, and accordingly can utilize a laser emitter and aphotodetector. Alternatively, the optical method can compriseellipsometry. If ellipsometry is utilized, elliptically polarized lightwill be directed toward layer 142 and a thickness of the layer will beestimated from one or more of a change in the elliptical polarization, achange in intensity, or a shift in the detected location of thereflected light. Regardless of the optical method utilized, such methodwill typically comprise emitting light from one or more emitters towardsusceptor surface 132 such that at least some of the light passes intoor through the material 142 formed over the susceptor surface. Theemitted light can then be detected with one or more photodetectors, andinformation about the detected light can be utilized to assess thethickness of the deposited material 142 on the susceptor surface. Theutilization of the information can incorporate a signal processorsimilar to the processor 117 described above with reference to FIG. 12.

The thickness of material 142 on the susceptor surface can be correlatedwith the thickness of the material over surface 140 of the semiconductorwafer substrate. Thus, a thickness and/or rate of growth of material 140on substrate 14 can be estimated from measurements of the material 140that is over surface 132.

The emitters and photodetectors utilized for the methodology of FIG. 15can be either within a reaction chamber comprising susceptor 12 andsubstrate 14, or can be external to such reaction chamber. If an emitterand/or detector is external of the reaction chamber, the light 150 canbe passed through one or more windows formed in sidewalls of thereaction chamber.

Referring to FIG. 16, wafer 14 is removed from susceptor 12.

Referring to FIG. 17, materials 134 and 142 are removed from oversurface 132. The processing of FIGS. 13-15 can then be repeated with asecond semiconductor substrate. Although both of materials 142 and 134are shown removed at the processing stage of FIG. 17, it is to beunderstood that only material 142 can be removed in some aspects of theinvention, and material 134 can remain during processing with a secondsemiconductor wafer. It is also to be understood that both materials 134and 142 can be left over surface 132 in some aspects of the invention,and the processing repeated with a second semiconductor wafer, with thenew deposited material being deposited over both a surface of thesemiconductor material and over an outer surface of material 142.

The removal of materials 142 and 134 can be conducted with, for example,hydrochloric acid, in aspects in which materials 134 and 142 comprise,consist essentially of, or consist of silicon, germanium, orsilicon/germanium.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1-16. (canceled)
 17. A deposition apparatus, comprising: a substratesusceptor for receiving a semiconductor wafer substrate; one or morelamps for providing radiant energy to the substrate, the radiant energybeing in the form of light waves; and a disperser between at least oneof the lamps and the substrate; at least some of the light waves beingpassed through the disperser prior to providing radiant energy to thesubstrate.
 18. The apparatus of claim 17 wherein the disperser comprisesa diffraction grating.
 19. The apparatus of claim 18 wherein thesusceptor is within a reaction chamber and wherein the disperser isoutside of the reaction chamber.
 20. The apparatus of claim 18 whereinthe susceptor is within a reaction chamber and wherein the disperser iswithin the reaction chamber.
 21. The apparatus of claim 17 wherein twoadjacent lamps provide radiant energy to the substrate, and whereinthere is sufficient dispersion of energy from the lamps that at least50% of the radiant energy impacting the substrate from one of the lampsis overlapped by radiant energy impacting the substrate from the otherof the lamps.
 22. The apparatus of claim 17 wherein two adjacent lampsprovide radiant energy to the substrate, and wherein there is sufficientdispersion of energy from the lamps that at least 70% of the radiantenergy impacting the substrate from one of the lamps is overlapped byradiant energy impacting the substrate from the other of the lamps. 23.The apparatus of claim 17 wherein two adjacent lamps provide radiantenergy to the substrate, and wherein there is sufficient dispersion ofenergy from the lamps that at least 90% of the radiant energy impactingthe substrate from one of the lamps is overlapped by radiant energyimpacting the substrate from the other of the lamps. 24-67. (canceled)